The invention relates to a structure for a motor vehicle, particularly a passenger car, having a front wall delimiting a passenger cabin toward the front, which front wall extends between lateral vehicle pillars of the structure, and to a method for producing such a structure.
Structures of the above-mentioned type are sufficiently known from the series production of passenger cars. Such a structure comprises a front wall which delimits a passenger cabin of a motor vehicle toward the front in a longitudinal direction of the vehicle. The front wall extends in a transverse direction of the vehicle between lateral vehicle pillars of the structure.
Such a structure is also known from DE 10 2006 055 721 A1. That structure also includes a central tunnel and a front wall cross member having two side parts attached to the lateral vehicle pillars, and a middle part connecting the two side parts. The side parts of the front wall cross member are formed such that they bear at least to some extent against the front wall and are also connected to the front wall. The middle part bears at least to some extent against the central tunnel and is disposed at a distance from the front wall. The front wall cross member is arranged in a longitudinal direction of the vehicle behind the front wall and is overlapped toward the front by the front wall. Experience has shown that such a structure, in case of accident-related application of force to the motor vehicle, has an accident behavior in need of improvement.
Therefore, the problem addressed by the present invention is that of further developing a structure for a motor vehicle, particularly a passenger car, and a method for producing a structure of the initially described type such that the structure exhibits an improved accident behavior.
This problem is solved with a structure for a motor vehicle, and a method of producing same, particularly a passenger car, having a front wall delimiting a passenger cabin toward the front, which front wall extends between lateral vehicle pillars of the structure. A carrier element, which extends in a transverse direction of the vehicle, is supported by a front side of the front wall and at least to some extent overlaps the lateral vehicle pillars.
Such a structure for a motor vehicle, particularly a passenger car, comprises a front wall which delimits a passenger cabin of a motor vehicle toward the front in a longitudinal direction of the vehicle. The front wall extends in a transverse direction of the vehicle between lateral vehicle pillars of the structure.
According to the invention, a carrier element is provided which, relative to the longitudinal direction of the vehicle, is supported by a front side of the front wall, extends in the transverse direction of the vehicle, and at least to some extent overlaps the lateral vehicle pillars toward the front. The carrier element is thus a support member for supporting or absorbing, and advantageously diverting, accident-related loads, particularly in case of a frontal impact collision of the motor vehicle. The front wall and thus the passenger cabin (cell) can be protected from unwanted damage in case of an accident-related application of force to the motor vehicle, particularly in case of a frontal impact collision, and unwanted intrusions into the passenger cabin can be prevented. This is beneficial to the safety of the occupants of the passenger cabin. The structure according to the invention thus exhibits improved accident behavior.
In particular, the function of the carrier element is that of holding off accident-related loads, i.e. impact forces or impact energies, at least to some extent, from the front wall and to divert said loads to the structures of the structure arranged behind the carrier element in the longitudinal direction of the vehicle. Since the carrier element overlaps the vehicle pillars at least toward the front, accident-related loads can advantageously be introduced into the vehicle pillars.
Preferably, lateral side sills, adjoining the vehicle pillars toward the bottom in the vertical direction of the vehicle, extending at least substantially in the longitudinal direction of the vehicle, are at least to some extent overlapped toward the front by the carrier element in the longitudinal direction of the vehicle. The accident-related loads can thus also be diverted by means of the carrier element to the side sills and by means of said side sills directed around the passenger cabin. As a result, the risk of unwanted damage to the passenger cabin can be kept particularly low.
The carrier element of the structure according to the invention can absorb and support accident-related loads since the carrier element is arranged in front of the front wall in the longitudinal direction of the vehicle. The carrier element can also function as a sacrificial component by deforming and/or collapsing due to energy absorption in case of the accident-related application of force. As a result, it is possible to convert the impact energy at least to some extent to deformation energy, reduce said impact energy and keep it away from the passenger cabin and thus the occupants of the motor vehicle. The front wall can thus withstand the accident-related application of force without unwanted damage.
In a particularly advantageous embodiment of the invention, the carrier element is made at least substantially of a fiber-reinforced plastic. As a result, the carrier element has a particularly high rigidity and/or strength. This is beneficial to the advantageous accident behavior of the structure according to the invention. Particularly, it is possible to adequately adjust the carrier element to loads occurring particularly during accident-related application of force and to design its form and/or wall thickness accordingly. It is further advantageous that the weight of the carrier element and thus of the entire structure can be kept particularly low. The high rigidity is advantageous for a very high overall rigidity of the structure, resulting in very favorable driving dynamics properties of the motor vehicle.
The fibers of the fiber-reinforced plastic embedded at least to some extent in the plastic of the carrier element can be fiberglass, aramid fibers, carbon fibers and/or other fibers with which the plastic of the carrier element is reinforced.
Preferably, the carrier element made of fiber-reinforced plastic is produced by means of a resin transfer molding (RTM) method, also called transfer molding. The carrier element can thus be produced time- and cost-effectively and adequately. The plastic of the carrier element is, e.g., a thermoset or an elastomer.
The carrier element made of fiber-reinforced plastic can be formed from one or more fabric layers, particularly fiber mats. The fabric layers or fiber mats can be pre-formed fabric layers or fiber mats, which are called preforms and which are provided with the plastic. For example, the plurality of fabric layers or fiber mats are arranged, connected to each other and formed with mutual overlapping in appropriate overlap regions. The fabric layer or layers are provided with the plastic which is the matrix material for receiving the fibers. As a result, the carrier element can be designed in one piece as a particularly rigid, strong and light fiber-plastic composite component. For reasons of simplifications, only the term fiber mat or fiber mats will be used in the following. It is understood that this can also denote fabric layers.
For the adequate and load-adjusted design of the carrier element, e.g., at least two of the fiber mats, from which the carrier element is produced, have thicknesses which differ from one another. As a result, the carrier element can have different wall thicknesses in at least two regions and thus correspondingly different properties.
Alternatively or additionally, in a first portion, the carrier element can have a first wall thickness which is greater than an at least second wall thickness in a second portion adjoining the first portion of the carrier element, wherein the first greater wall thickness is formed by the plastic of the carrier element. In other words, the carrier element is thickened in the first portion by means of the plastic, as compared to the second portion, and designed suitably adequate.
Alternatively or additionally, it is possible that the greater first wall thickness is formed in the first portion such that a greater number of fiber mat layers are provided in the first portion than in the second portion. For example, a first fiber mat is provided in the first portion and in the second portion, wherein in the first portion, at least one further fiber mat is additionally arranged, overlapping with the first fiber mat.
Such a plurality of fiber mat layers is also depicted in the overlap region, in which the fiber mats, of which the carrier element is made, mutually overlap. In the overlap region, the carrier element has a greater wall thickness than in at least one adjoining further region with no overlap. For example, the overlap region or—if a plurality of overlap regions are provided—the overlap regions can be arranged such that the structure according to the invention is provided with an advantageous and load-adjusted accident behavior.
It is further possible that the fiber mats, fabric layers or fiber mat layers differ from one another with regard to their composition, structure and/or with regard to their respective fiber direction. As a result, the fiber mats or fabric layers can be designed adequately and functionally adjusted with regard to their load-bearing and load-diverting capabilities because, depending on structure and or fiber direction, load paths can be created for absorbing and diverting particularly accident-related loads.
Furthermore, the fiber mat or fabric layer can be aligned with regard to its fiber direction and/or adequately designed with regard to its composition or structure. As a result, load paths for absorbing and diverting loads can be aligned functionally adjusted since the direction of the load paths and thus the load-bearing capability depends particularly on the fiber direction and/or the structure.
In a further advantageous embodiment, the front wall is at least predominantly overlapped toward the front by the carrier element in the longitudinal direction of the vehicle. The carrier element is thus a second wall element in addition to the front wall, with which the front wall can be protected in case of an accident-related application of force on the motor vehicle.
Preferably, the carrier element is also supported, particularly through bypassing the front wall, in the longitudinal direction of the vehicle by a vehicle floor of the structure according to the invention. Thus, an advantageous load path is formed, with which the accident-related loads can be diverted into the vehicle floor—without being transmitted through the front wall—and thus kept away from the front wall. This results in a particularly favorable accident behavior of the structure according to the invention.
In a further advantageous embodiment of the invention, the carrier element is supported at least in a first portion by the front wall and in at least a second portion by the vehicle pillars. In other words, the carrier element is in support contact with the vehicle pillars, and therefore an advantageous support and diverting of the accident-related loads to the vehicle pillars is realized.
In a further advantageous embodiment, the front wall is provided with a front wall cross member, with which the carrier element is supported. The front wall cross member extends in the transverse direction of the vehicle and is arranged in the vertical direction of the vehicle in an upper region of the front wall or above said front wall. Due to the support of the carrier element by the front wall cross member, the accident-related loads can be also diverted from the carrier element to the front wall cross member.
Preferably, the front wall cross member is attached to the lateral vehicle pillars. The accident-related loads can thus be further diverted from the front wall cross member into the vehicle pillars and kept away from the passenger cabin.
In a further advantageous embodiment of the invention, the carrier element overlaps at least sections, particularly at least predominantly, of the front wall cross member toward the front in the longitudinal direction of the vehicle. As a result, the carrier element can initially absorb the accident-related loads and divert said loads specifically to the front wall cross member positioned behind the carrier element in the longitudinal direction of the vehicle.
Advantageously, the front wall cross member is at least substantially made of a fiber-reinforced plastic, thus having high rigidity, strength and low weight.
In a further advantageous embodiment, at least one gap is formed between the front wall and the carrier element, in which a bridging element supported by the front wall and the carrier element is arranged. As a result, targeted absorption and diverting of accident-related forces can be achieved, which is advantageous for the protection of the front wall. This is particularly the case if a support element on a rear side of the front wall, which is facing away from the carrier element and the bridging element and which is facing the passenger cabin, is supported by both the front wall and at least one structural component arranged in the longitudinal direction of the vehicle behind the front wall. As a result, loads introduced to the front wall by means of the bridging element can be directly diverted from the front wall and introduced into the structural component arranged behind the front wall. This provides a very advantageous load path. The structural component, for example, can be a tunnel element of the vehicle floor.
For adequate and local strengthening of the carrier element, it is provided with at least one reinforcement element. As a result, particularly the mechanical properties of the carrier element can be adequately and locally adjusted to the occurring loads.
Preferably, the bridging element and/or the reinforcement element are at least substantially made of a metallic material. The bridging element and/or the reinforcement element can be made from a steel, aluminum or aluminum alloy, or other light metal, particularly another light metal alloy. The bridging element and/or the reinforcement element can thus have particularly advantageous ductility and/or strength which are advantageous for the accident behavior of the carrier element and thus the structure according to the invention. A high ductility of the reinforcement element and/or the bridging element contributes to the efficient conversion of the accident-related loads to deformation energy. A particularly high strength results in high structural integrity of the carrier element, so the passenger cabin can be advantageously protected.
The bridging element and/or the reinforcement element can be designed as an extruded profile with at least one chamber. They can thus be produced time- and cost-effectively and have advantageous mechanical properties.
In a further advantageous embodiment, the bridging element and/or the reinforcement element has at least one fastener for fastening a front module of the vehicle and/or another attachment part to the structure. The fastener, for example, can be a screw boss and/or a screw-in opening, so the possibly metallic front module or the possibly metallic attachment part can be bolted tightly to the carrier element and thus be connected to the carrier element.
If the carrier element is made at least substantially of a fiber-reinforced plastic, the reinforcement element and/or the bridging element are preferably made of a metallic material. Thus, the fastener is also made of a metallic material. This allows for a strong and corrosion-preventing connection of the front module and/or the attachment with the carrier element.
The front module, for example, has an auxiliary member for holding a drive unit of the motor vehicle and/or an ancillary unit. The drive unit, for example, is at least one electric motor by which the motor vehicle can be powered.
In a further particularly advantageous embodiment of the invention, at least one support element for a spring and/or damping element of a chassis of the motor vehicle is provided. The support element supports and connects the spring and/or damping element to the structure, so the support element can absorb and support forces from the spring and/or damping element. The support element is supported, particularly in the longitudinal direction of the vehicle, by the carrier element. Advantageously, the support of the support element by the carrier element has a great, particularly extensive, extension. As a result, the spring and/or damping element are solidly and rigidly supported by the structure. This contributes to very favorable driving dynamics of the motor vehicle.
If the carrier element is adhesively bonded with the front wall, the vehicle pillars and/or the front wall cross member, the weight of the structure is kept low. It also realizes a particularly tight and corrosion-preventing connection.
In a further advantageous embodiment of the invention, the front wall, the support element, the vehicle pillars and/or the side sills are made at least substantially of a fiber-reinforced plastic. As a result, the weight of the structure and thus the motor vehicle is kept low, and the motor vehicle can be powered with a low energy requirement. Furthermore, this ensures a high rigidity of the structure which is associated with advantageous driving dynamics properties of the motor vehicle.
Preferably, the structure according to the invention is designed as a self-supporting vehicle body for a passenger car.
The invention also relates to a method for producing a structure, particularly a structure according to the invention, for a motor vehicle. The structure comprises a front wall, delimiting the passenger cabin of the motor vehicle toward the front, and which extends between lateral vehicle pillars of the structure.
According to the invention, a carrier element extending in the longitudinal direction of the vehicle is supported by a front side of the front wall and at least sections are arranged overlapping the vehicle pillars. Advantageous embodiments of the structure according to the invention must be considered to be advantageous embodiments of the method according to the invention, and vice versa.
The method according to the invention allows for the realization of an improved accident behavior of the structure since the carrier element, due to its arrangement and support, can protect the front wall against unwanted damage. Unwanted intrusions into the passenger cabin can thus be prevented, resulting in great safety for the occupants of the motor vehicle.
Within the framework of the method according to the invention, the vehicle pillars and the side sills, adjoining the vehicle pillars toward the bottom in the vertical direction of the vehicle, and the front wall with the front wall cross member are initially produced and joined with one another. In addition, further components of the structure can be produced and joined. Then, the carrier element is arranged in front of the front wall and joined with the front wall and, preferably, the vehicle pillars, the front wall cross member, and the side sills, and appropriately supported by said front wall, so that the front wall, the vehicle pillars, the front wall cross member, and the side sills are overlapped toward the front by the carrier element.
As a result, the carrier element initially absorbs the accident-related loads in case of a frontal impact collision of the motor vehicle with a barrier and specifically diverts said loads to structures arranged behind the carrier element, such as the vehicle pillars, the front wall cross member, and the side sills, and at least predominantly keeps said loads away from the front wall for its protection.
The carrier element is joined with the front wall and possibly with the front wall cross member, the vehicle pillars, and the side sills during assembly of the structure. This allows for a time- and cost-effective production.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.